:root {
  --primary: #1e3c72;
  --primary-light: #2a5298;
  --secondary: #6a3093;
  --accent: #f7931a;
  --accent-alt: #27ae60;
  --text: #333;
  --light: #f8f9fa;
  --dark: #212529;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Roboto', 'Montserrat', sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: linear-gradient(135deg, #f5f7fa 0%, #e4e8eb 100%);
  min-height: 100%;
  overflow-x: hidden;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: white;
  padding: 2rem 0;
  position: relative;
  overflow: hidden;
}

header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: 0;
}

.header-content {
  position: relative;
  z-index: 1;
  text-align: center;
}

h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
  background: linear-gradient(to right, white, #f5f5f5);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.tagline {
  font-size: 1.2rem;
  opacity: 0.9;
  margin-bottom: 2rem;
}

.notice {
  background: rgba(255,255,255,0.2);
  padding: 1rem;
  border-radius: 8px;
  display: inline-block;
  margin-top: 1rem;
  backdrop-filter: blur(5px);
}

nav {
  background: rgba(0,0,0,0.7);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(5px);
}

.nav-container {
  display: flex;
  justify-content: center;
  padding: 1rem 0;
}

.nav-link {
  color: white;
  text-decoration: none;
  padding: 0.5rem 1.5rem;
  margin: 0 0.5rem;
  border-radius: 4px;
  transition: all 0.3s ease;
  position: relative;
}

.nav-link:hover {
  background: rgba(255,255,255,0.2);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: all 0.3s ease;
}

.nav-link:hover::after {
  width: 70%;
  left: 15%;
}

article {
  background: white;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  padding: 3rem;
  margin: 3rem 0;
  position: relative;
  overflow: hidden;
}

article::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 200px;
  height: 200px;
  background: url('https://images.gptkong.com/demo/sample2.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: 0;
}

h2 {
  font-size: 2rem;
  color: var(--primary);
  margin: 2rem 0 1rem;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(to right, var(--accent), var(--accent-alt));
}

h3 {
  font-size: 1.5rem;
  color: var(--secondary);
  margin: 1.5rem 0 1rem;
}

p {
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
  position: relative;
  z-index: 1;
}

.img-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin: 2rem 0;
}

.img-card {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  transition: all 0.3s ease;
  position: relative;
}

.img-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

.img-card img {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.5s ease;
}

.img-card:hover img {
  transform: scale(1.05);
}

pre {
  background: #282c34;
  color: #abb2bf;
  padding: 1.5rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 2rem 0;
  font-family: 'Courier New', monospace;
  font-size: 0.95rem;
  line-height: 1.5;
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  left: 0;
  background: var(--accent);
  color: white;
  padding: 0.2rem 0.8rem;
  border-radius: 0 0 4px 0;
  font-size: 0.8rem;
}

code {
  font-family: 'Courier New', monospace;
  background: rgba(0,0,0,0.05);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9rem;
}

footer {
  background: linear-gradient(135deg, var(--dark) 0%, #343a40 100%);
  color: white;
  padding: 3rem 0;
  text-align: center;
  margin-top: 3rem;
}

.footer-content {
  max-width: 800px;
  margin: 0 auto;
}

.footer-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  margin: 1.5rem 0;
}

.footer-link {
  color: white;
  text-decoration: none;
  margin: 0 1rem;
  opacity: 0.8;
  transition: opacity 0.3s ease;
}

.footer-link:hover {
  opacity: 1;
  color: var(--accent);
}

@media (max-width: 768px) {
  h1 {
    font-size: 2.2rem;
  }
  
  article {
    padding: 2rem;
  }
  
  .img-container {
    grid-template-columns: 1fr;
  }
}

@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

.floating {
  animation: float 3s ease-in-out infinite;
}